This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
A rotorcraft may include one or more rotor systems. One example of a rotorcraft rotor system is a main rotor system. A main rotor system may generate aerodynamic lift to support the weight of the rotorcraft in flight and thrust to counteract aerodynamic drag and move the rotorcraft in forward flight. Another example of a rotorcraft rotor system is a tail rotor system. A tail rotor system may generate thrust to counter the torque effect created by the main rotor system.
The control systems for rotorcraft are complex electrical and/or mechanical systems. The control systems respond to the pilot's input, but also must accommodate external forces acting upon the rotor assemblies which are generally outside the control of the pilot. Mechanical control systems typically include a swashplate arrangement which consists of a nonrotating portion and a rotating portion. Pilot inputs applied to the nonrotating portion alter the vertical position of the swashplate through the collective control and the tilt of the swashplate through the cyclic control.
Most rotorcraft control systems incorporate hydraulic boost actuators to increase the control force of the pilot input to overcome the external forces acting on the main rotor system. In rotorcraft in which the control forces are so high that they cannot be moved without hydraulic assistance, two or more independent hydraulic boost systems may be incorporated as a failsafe.
Control input forces can be mechanically boosted in tail rotor systems through counterweights due to the high speed of rotation of tail rotors. However, heretofore, counterweight systems have not been applicable for mechanically boosting control inputs in main rotor systems.